Herbicide

ABSTRACT

This invention relates to a herbicidal composition comprising fosmidomycin or salt thereof in combination with the other herbicide selected from the group of ametryn or salt thereof or diuron, and to a method of killing weeds by applying to weed seedlings the said combination.

This invention relates to a new herbicide.

More particularly, it relates to a new herbicidal composition comprisingfosmidomycin or salt thereof in combination with the other herbicideselected from the group or ametryn or salt thereof or diuron, and to amethod of killing weeds by applying to weed seedlings the saidcombination.

The fosmidomycin is a known compound,3-(N-formyl-N-hydroxyamino)propylphosphonic acid as antibacterial agent[Cf. European Journal of Drug Metabolism and Pharmacokinetics Vol. 7,P59 (1982)] and as herbicide [Cf. Japan Kokai No. 106504/1986].

Further, ametryn and diuron are also known herbicides,2-methylmercapto-4-ethylamino-6-isopropylamino-s-triazine and3-(3,4-Dichlorophenyl)-1,1-dimethylurea, respectively [Cf. The MerckIndex tenth edition items 392 and 3400 (1983)].

The fundamental physiological action of fosmidomycin resides in theinhibition of production of chlorophyll. Therefore, plants emergingafter treatment with fosmidomycin are ready to undergo chlorosis. Whenthe treating concentration is such that this chlorosis lasts as long asmore than 2 to 3 weeks, arrest of growth occurs as the plant isprevented from nursing itself by photosyntheses, leading to decay.However, as the treating concentration is decreased, the degree andduration of chlorosis are lessened and the plant will not die but show arecovery of growth so that the object of killing cannot be accomplished.While a large variety of herbicides have been developed and put to usefor controlling the weeds detrimental to crop plants and theenvironment, each of these herbicides has its own drawback orshortcoming and none has ever proved fully satisfactory in weed killingeffect.

Thus, what are mainly desired in herbicides are:

(1) The maximum possible coverage of weed varieties that can becontrolled (a broad herbicidal spectrum)

(2) Manifestation of sufficient control effect within the shortestpossible time after application (a reduced number of days required forcomplete weed control)

(3) No variation in effect according to the volume and height of weedsor an improved stability of control effect (stabilized weed controleffect).

(4) Reduced amounts of active substances required for control (reducedherbicide consumption)

The present inventors discovered that application of a compositioncontaining fosmidomycin or salt thereof in combination with the otherherbicide selected from the group of ametryn or salt thereof and diuronto a plant resulted in a surprisingly great synergistic herbicidaleffect on the plant. This finding was followed by a furtherinvestigation, which culminated in the present invention.

The salt of fosmidomycin may include an agronomically acceptable saltthereof such as a base salt (e.g. sodium salt, potassium salt, calciumsalt, etc.) and the like.

The salt of ametryn may include an agronomically acceptable salt thereofsuch as an acid addition (e.g. hydrochloride, sulfate, phosphate, etc.)and the like.

The herbicidal composition according to the present invention displaysremarkable efficacy as a postemergence herbicide, and is preferablyapplied to the whole stalks and foliage of weeds that have emerged.

Moreover, the herbicidal composition of the present invention provideseffective control, irrespective of weed variety, e.g. broad-leaved weedsand grasses.

The application rate for the active ingredients in the herbicidalcomposition of the invention varies according to the combination usedand kinds of weeds to be controlled. Generally however, the optimum rateof application is selected from the range of 5 to 1000 grams/10 ares andpreferably from the range of 100 to 500 grams/10 ares.

The ratio of the fosmidomycin or a salt thereof to the ametryn or a saltthereof or diuron in the herbicidal composition of the invention isdependent on the kinds of respective compounds and the kinds of weeds tobe controlled.

Generally, the ratio is selected from the range of 10:1 to 1:10,preferably 6:1 to 1:6.

To apply the herbicidal composition of the invention, it can be mixedwith a carrier suited to the intended usage and applied in such variedforms as dusts, granular preparations, wettable powders, liquidpreparations, emulsifiable concentrates, flowable emulsion concentratesand so on. The carrier mentioned just above may be a solid or a liquidcarrier or a combination thereof. As examples of said carrier, there maybe mentioned finely divided minerals such as kaolinite, bentonite,pyrophyllite, talc, diatomaceous earth, silica gel, calcium carbonate,etc., finely divided vegetable materials such as starch, gum arabic,etc., organic solvents such as alcohols, ketones, kerosine, benzene,toluene, xylene, cyclohexane, methylnaphthalene, dioxane,dimethylformamide, dimethyl sulfoxide, corn oil, o-dichlorobenzene,isophorone, water and so on. Further, agronomically acceptable adjuvantsand auxiliaries such as wetting agents, dispersing agents, adhesives,extenders, etc. can be incorporated, if necessary, in appropriateproportions.

Each of these preparations is not only useful as such but may be used incombination with bactericides, fungicides, nematocides, insecticides,plant growth regulators, fertilizers, other herbicides and so on.

The following reference and working examples are intended to illustratethe invention in further detail.

REFERENCE EXAMPLE

Seeds of the following species of plants were sown in soil-filled pots(30 cm long×10 cm wide×10 cm deep) and grown in a glasshouse. After 2weeks, seedlings which had grown to a height of 5 to 20 cm were treatedwith test compound. The test compound was dissolved in water and thesolution was adjusted to a application concentration of 500 ppm or 5000ppm and applied to the whole surface of the plant at the rate of 100liters water/10 ares. Control pots were treated with water only. After10, 20 and 30 days following application, the plants were observed forgrowth and the control effect of the test compound was evaluated.

The test plants were as follows.

    ______________________________________                                                Test plant                                                            No.     Common name   Botanical name                                          ______________________________________                                        1       Rice          Oryza sativa L.                                         2       Maize         Zea mays L.                                             3       Barnyard millet                                                                             Panicum Crus-galli L.                                   4       Crabgrass     Digitaria adscendes Henr.                               5       Soybean       Glycine Max MERR.                                       6       Convolvulus   Calystegia japonica choisy                              7       Barnyard grass                                                                              Amaranthus Blitum L                                     ______________________________________                                    

The test compound is as follows.

    ______________________________________                                        Compound No.                                                                              Chemical name                                                     ______________________________________                                        1           3-(N--Formyl-N--hydroxyamino)propyl-                                          phosphonic acid monosodium salt                                   ______________________________________                                    

The test results are set forth below in the table. Control effects werescored on a rating scale of 0 for no effect through 100 for completecontrol (complete kill).

    ______________________________________                                        Com-   Time                                                                   pound  after                                                                  No.    appli-   Plant No.                                                     (concen-                                                                             cation in                                                                              Herbicidal activity (%)                                       tration                                                                              days     1      2    3    4    5    6    7                             ______________________________________                                        1      10        ○22                                                                           ○27                                                                         ○34                                                                         ○40                                                                         ○46                                                                         ○25                                                                         ○28                   (500 ppm)                                                                            20        ○56                                                                           ○44                                                                         ○61                                                                         ○67                                                                         ○60                                                                         ○40                                                                         ○43                          30       38     31   55   52   42   30   27                            1      10        ○51                                                                           ○65                                                                         ○72                                                                         ○78                                                                         ○59                                                                         ○52                                                                         ○69                   (5000  20       100    100  100  100  100  100  100                           ppm)   30       100    100  100  100  100  100  100                           ______________________________________                                    

The open circle around each figure indicates the occurrence ofchlorosis.

EXAMPLE 1

Using the same test plant species and the same test procedure asdescribed in Reference Example, the control effects of the followingcompounds were tested and evaluated.

The observation of plants for growth status was made on 10 days afterapplication.

The test compounds are as follows.

    ______________________________________                                        Compound                                                                      No.     Chemical name (concentration)                                         ______________________________________                                        1       2-Methylmercapto-4-ethylamino-6-isopropylamino                        s-triazine 1*                                                                         (500 ppm)                                                             2       2-Methylmercapto-4-ethylamino-6-isopropylamino                        s-triazine 1*                                                                         (500 ppm)                                                                     +                                                                             3-(N--Formyl-N--hydroxyamino)propylphosphonic                                 acid monosodium salt                                                          (500 ppm)                                                             3       3-(N--Formyl-N--hydroxyamino)propylphosphonic                                 acid monosodium salt                                                          (500 ppm)                                                             ______________________________________                                         Note                                                                          As test compounds 1*, the corresponding commercial product Gesapax (25%       emulsifiable concentrate, CibaGeigy) was used.                           

The test results are shown below in the table.

    ______________________________________                                                Plant No.                                                                     Hibicidal activity (%)                                                Compound No.                                                                            1      2       3    4    5    6     7                               ______________________________________                                        1          78     82     100  100  100   80    78                             (Control)                                                                     2         100    100     100  100  100  100   100                             3          ○22                                                                           ○27                                                                            ○34                                                                         ○40                                                                         ○46                                                                         ○25                                                                          ○28                     (Control)                                                                     ______________________________________                                    

The open circle around each figure indicates the occurrence ofchlorosis.

EXAMPLE 2

The field on which the following weeds were grown, were plotted out in aratio of 4 m² /lot.

The following test compound was dissolved in water at the specifiedapplication rate and was sprayed onto the whole surface of the weeds atthe volume rate of 100 liters water/10 ares.

Control lots were treated with water only.

    ______________________________________                                        Test weed                                                                             Test weeds   Botanical       height                                   code    common name  name            (cm)                                     ______________________________________                                        a       Fleabane, Annul                                                                            Erigeron annuus L.                                                                            60                                       b       Ohinutade    Polygonum Blumei                                                                              60                                                            Meisn                                                    c       Clover, Red  Trifolium protense L.                                                                         40                                       d       Mugwort      Artemisia vulgaris L.                                                                         40                                                            var. indica Maxim                                        e       Dandelion    Taraxacum Officinale                                                                          10-20                                                         Weber                                                    f       Brome, Rescue                                                                              Bromus unioloides                                                                             60                                                            Humb. Bonpl. et Kunth                                    ______________________________________                                        Test compound No.                                                                            Chemical name                                                  ______________________________________                                        A              3-(N--Formyl-N--hydroxyamino)-                                                propylphosphonic acid                                                         monosodium salt                                                B              2-Methylmercapto-4-ethylamino-6-                                              isopropylamino-s-triazine 1**                                  C              3-(3,4-Dichlorophenyl)-1,1-                                                   dimethylurea 2**                                               ______________________________________                                         Note                                                                          As test compounds 1** and 2**, the corresponding commercial products,         Gesapax (25% emulsifiable concentrate, CibaGeigy) and Karmex D(78.5%          wettable powder, du Pont) were used, respectively.                       

Two weeks after the treatment, herbicidal effect of the test compoundson the weeds were observed and scored on a rating scale of 0 for noeffect through--100 for complete kill.

    ______________________________________                                        Test compound                                                                 and application                                                               rate (g/10a)                                                                           Test weed and herbicidal activity (%)                                ______________________________________                                        B     A      a       b     c     d     e     f                                ______________________________________                                        0      25     5       5     5    10    10     0                               0      50    10      10    10    15    10    10                               0     100    20      20    20    30    15    10                               62.5   0      0       0     0     0     0     0                               125    0     20      20    15    20    10    15                               250    0     40      50    60    60    60    55                               62.5   25    60      60    50    60    70    60                               125    25    70      65    70    80    70    70                               250    25    85      80    85    80    85    80                               62.5   50    70      70    75    80    70    70                               125    50    80      80    90    90    80    80                               250    50    90      >90   90    >90   90    90                               62.5  100    80      90    80    >90   80    80                               125   100    90      >90   >90   >90   90    90                               250   100    >90     >90   >90   >90   >90   >90                              ______________________________________                                        C     A      a       b     c     d     e     f                                ______________________________________                                        0      25     5       5     5    10    10     0                               0      50    10      10    10    25    10    10                               0     100    20      20    20    30    15    10                               250    0      5       5    10     5    10     5                               500    0     15      10    20    15    20    15                               750    0     40      30    40    30    40    30                               250    25    40      50    30    50    50    40                               500    25    60      60    40    50    55    60                               750    25    85      80    75    85    85    85                               250    50    60      70    50    70    60    60                               500    50    80      90    80    90    90    85                               750    50    90      90    90    >90   90    90                               250   100    85      90    80    90    80    70                               500   100    90      >90   >90   >90   >90   >90                              750   100    >90     >90   >90   >90   >90   >90                              ______________________________________                                    

EXAMPLE 3

Seeds of goosefoot were sown in soiled polyethylene pots (20 cm long×10cm wide×10 cm deep) and grown in a glasshouse. Numbers of seedlings(Grown height: 30 cm) were adjusted to 10/pot. Each test compound wasdissolved in water at the specified application rate and applied ontothe leaves and stocks of Goosefoot. The treated goosefoot were grown ina glass house at 25°-30° C. for 2 weeks. The weight of the remaining andliving portion (above ground) of groose foot was determined and from theobtained data, ratio (%) of the weight of treatment group to that ofnon-treatment group was calculated. The results are shown in thefollowing table (a).

(a) Ratio (%) of the remaining weight of the treated plant to that ofthe non-treated plant

    ______________________________________                                                        application rate (g/10a) of                                                   the test compound A                                                           0     25     50      100                                      ______________________________________                                        application rate (g/10a)                                                                    0       100     95   85    85                                   of the test compound B                                                                      62.5    100     45   25    10                                                 125      80     20   10    <10                                                250      50     10   10    <10                                  ______________________________________                                         Note:                                                                         Test compound A: 3(N--formyl-N--hydroxyamino)-propylphosphonic acid           monosodium salt                                                               Test compound B: 2methylmercapto-4-ethylamino-6-isopropylamino-s-triazine     [Gesapax (25% emulsifiable concentrate, CibaGeigy)]-                     

The above data were analyzed according to Colby's equation (cf. weeds,Vol, 15, P. 20-22).

    ______________________________________                                        Expected value (%) of the remaining weight of the                             plant treated with the combination                                            ______________________________________                                        Obserbed value (%) of the                                                                    ×  Observed value (%) of                                 remaining weight of the the remaining weight                                  plant treated with      of the plant treated                                  compound A only         with compound B only                                  ______________________________________                                    

In case that the expected value (%) is larger than the observed value(%), the combination can be judged to have synergistic effect.

The Colby's expected values (%) obtained by calculating using the abovedata are shown in the following table (b).

(b) Colby's expected value

    ______________________________________                                                        application rate (g/10a) of                                                   the test compound A                                                           25     50       100                                           ______________________________________                                        application rate (g/10a)                                                                    62.5    95       85     85                                      of the test compound B                                                                      125     76       68     68                                                    250     47.5     42.5   42.5                                    ______________________________________                                    

As clear from the data listed in the above table (a) and (b), allcombinations of the test compound A and B can be judged to havesynergistic herbicidal activity.

EXAMPLE 4

The following data were obtained in a similar manner to those of Example3, excepting the test compound C was used in place of the compound B.

(a) Ratio (%) of the remaining weight of the treated plant to that ofthe non-treated plant

    ______________________________________                                                         application rate (g/10a) of                                                   the test compound A                                                           0    25      50     100                                      ______________________________________                                        application rate (g/10a)                                                                     0       100    95    85   85                                   of the test compound C                                                                      250      95     60    40   20                                                 500      85     45    10   <10                                                750      60     20    10   <10                                  ______________________________________                                         Note:                                                                         Test compound A is the same compound as defined in Example 3.                 Test compound C: 3(3,4-dichlorophenyl)-1,1-dimethylurea[Karmex D (78.5%       wettable powder, du Pont)].                                              

(b) Colby's expected value (%)

    ______________________________________                                                       application rate (g/10a) of                                                   the test compound A                                                           25     50       100                                            ______________________________________                                        application rate (g/10a)                                                                    250    90       81     81                                       of the test compound C                                                                      500    81       72     72                                                     750    57       51     51                                       ______________________________________                                    

As clear from the data listed in the above table (a) and (b), allcombinations of the test compound A and C can be judged to havesynergistic herbicidal activity.

We claim:
 1. A herbicidal composition comprising a herbicidallyeffective amount of fosmidomycin or a salt thereof in combination withthe herbicide diuron, in a ratio of between 10:1 and 1:10, and anagronomically acceptable carrier or carriers.
 2. A method of killingbroad leaved weeds and grasses, said method comprising applying to broadleaf weeds or grass seedlings a herbicidally effective amount of acombination of fosmidomycin or a salt thereof and the herbicide diuron.3. The herbicidal composition of claim 1 wherein said ratio is between6:1 and 1:6.
 4. The method of claim 2 wherein said combination isapplied in an amount of 5 to 1000 g/1000 m².
 5. The method of claim 2wherein said combination is applied in an amount of 100 to 500 g/1000m².